Lignin sulfonates are produced from the naturally, occurring renewable material lignin through sulfonation. For the ease of reference, lignin sulfonate(s) are generally referred through out this application as LS.
Calcium LS (also known as calcium lignosulfonate), is a complex polymer of phenylpropane units, which are cross-linked to each other with a variety of different chemical bonds. Lignin is present in plant cells together with cellulose and hemicellulose. Lignin sulfonate is obtained as a by-product of paper manufacturing from tree pulps. Pulping is the term used for the process which separates wood fibers. Chemical pulping that dissolves the lignin in the wood to create a pulp, is the most common pulping process. The two main types of chemical pulping are the more common sulfate pulping (commonly known as Kraft pulping) and sulfite pulping.
The lubricants industry and, in particular, the lubricating grease industry, is interested in new replacements for molybdenum disulfide and other extreme pressure and anti-wear additives. Another incentive to find replacements for molybdenum disulfide and other additives is the ever increasing prices of these raw materials and their eroding supplies. Due to the decreasing supplies of oils and other petrochemical sources, the industry is now forced to find renewable resources, if possible, when formulating lubricants and lubricating greases.